解析带有多个参数的命令行选项[getopt?] [英] Parsing command line options with multiple arguments [getopt?]

问题描述

我需要我的程序从命令行获取多个参数，语法如下:

I need my program to get several arguments from command line, the syntax is as follows:

getpwd -l user1 user2 ... -L -X -S...

因此，我需要将用户吸引到-l选项的后面.我尝试使用getopt，但运气不佳，仅当将其他选项放在-l之前时，它才起作用:

So, I need to get the users behind the -l option. I tried using getopt, but without much luck, it only works when I place the other options before the -l:

getpwd -L -X -S ... -l user1 user2 ...

我的代码(用于-l和-S):

    while((c = getopt(argc, argv, "l:S")) != -1){
    switch(c){
        case 'l':
            index = optind-1;
            while(index < argc){
                next = strdup(argv[index]); /* get login */
                index++;
                if(next[0] != '-'){         /* check if optarg is next switch */
                    login[lcount++] = next;
                }
                else break;
            }
            break;
        case 'S':
            sflag++;                        /* other option */
            break;
        case ':':                           /* error - missing operand */
            fprintf(stderr, "Option -%c requires an operand\n", optopt);
            break;
        case '?':                           /* error - unknown option */
            fprintf(stderr,"Unrecognized option: -%c\n", optopt);
            break;
      }
   }

optopt和optind是extern int.

因此，问题是:我可以使用getopt()函数(或getopt_long())吗?还是我必须编写自己的解析器才能获得所需的内容?

So, the question is: Can I use the getopt() function (or getopt_long()) ? Or do I have to write my own parser to get what I need ?

推荐答案

您的代码实际上非常非常接近工作.您唯一缺少的是getopt仅希望您在-l之后使用一个参数，因此会在-l的第一个参数之后继续命令行解析.由于要退后一步并提取更多参数，因此必须告诉getopt从哪里开始重新解析命令行.

Your code was actually very, very close to working. The only thing you were missing is that getopt only expects you to consume one argument after -l, and therefore continues command line parsing following the first argument to -l. Since you're going behind its back and pulling off more arguments, you have to tell getopt where to start parsing the command line again.

getopt将该信息存储在全局变量optind中.当我添加该行时:

getopt stores that information in the global variable optind. When I added the line:

optind = index - 1;

在l情况下的break;之前，您的代码开始工作.

before the break; in your l case, your code started working.

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